The invention relates to a treadmill including a motor having an outer rotor.
A treadmill 100 of the prior art is shown in FIG. 1. FIG. 2 shows a top-plan-sectional view of certain aspects of the treadmill 100. As shown in FIGS. 1 and 2, the prior-art treadmill 100 generally includes a frame 105, a walking-belt drive assembly 110, a motor assembly 115, and control circuitry 118.
The control circuitry 118 includes a motor power supply 120 and a treadmill controller 123. As best shown in FIG. 2, the motor power supply 120 is electrically connected to the motor assembly 115. The treadmill controller 123 includes an input device (e.g., an on/off switch, one or more buttons, a control dial, an entry keypad, etc.) that allows an operator to operate the treadmill 100. For the prior art embodiment shown, the input device is an on/off switch 125 (FIG. 1). When the on/off switch 125 is on, the motor power supply 120 controllably transmits a power to the motor assembly 115. In other embodiments of the invention, the treadmill controller 123 may include artificial intelligence (e.g., a microprocessor and a memory unit having a software program) that interacts with the motor assembly 115 for better controlling the treadmill 100.
The motor assembly 115 receives the electrical power from the motor power supply 120 and converts the power into mechanical power. The mechanical power is provided to the walking-belt drive assembly 110. As best shown in FIG. 2, the motor assembly 115 includes a motor 127 having a housing 128, first and second bearings mounted in the housing 128, a stator, a rotor, a shaft 130 and one or more fasteners 135. For the prior art treadmill motor 127, the stator is directly coupled to the housing 128 and includes a motor back iron and magnets. The rotor is encircled by the stator, is supported by the shaft and bearings, and rotates within the stator. When the motor 115 receives power from the motor power supply 120, a magnetic field is created by the inner rotor that interacts with a magnetic field generated by the stator magnets. The interacting magnetic fields cause the rotor and, consequently, the motor shaft 130 to rotate.
The fastener 135 couples the motor 127 to the frame 105 and prevents the stator, including the magnets and back iron, from moving. For the prior art embodiment shown, the fastener is a mounting base.
The prior art motor assembly 115 further includes a flywheel 140 directly mounted on the shaft 130 and located externally to the motor 127. The flywheel 140 includes a first pulley 145 directly coupled to the flywheel 140. The flywheel 140 provides a smoothing affect to the motor 127. In other words, if the load (i.e. the walking-belt drive assembly 110) attached to the first pulley 145 varies (i.e., a person is walking or running on the treadmill), then the flywheel 140 evens out the varying load. Specifically, the demand or load on the motor assembly 115 increases each time the operator's foot contacts the walking belt 160 (discussed below), resulting in the operator transferring his weight to his foot. Due to the flywheel 140 having inertia, the flywheel 140 evens out the varying load.
As shown in FIG. 2, the walking-belt drive assembly 10 includes a pulley belt 150 movably coupled with the motor assembly 115, a first roller 155 rotatably mounted to the frame 105 and movably coupled to the pulley belt 150, a walking-belt 160 movably coupled to the first roller 155, a second pulley 157 directly coupled to the first roller 155, and a second roller (not shown) rotatably mounted to the frame 105 and movably coupled to the walking belt 160. Upon the motor assembly 115 causing the pulley belt 150 to move, the pulley belt 150 rotates the first roller 155. The rotation of the first roller 155 results in the walking belt 160 continuously rotating around the first and second rollers. This allows a user to walk or run on the walking belt 160. Of course, other conveyers or conveyer systems may be used in place of the first roller, second roller, and walking belt.
When a user is walking or running on the walking belt 160, a varying load (typically referred to as a “shock load”) is introduced to the walking-belt drive assembly 110. Due to elements of the walking-belt drive assembly 110 interconnecting, the varying load is translated to the motor assembly 115 via the pulley belt 150.
As can be seen from FIGS. 1 and 2 and the description above, the treadmill 100 of the prior art includes a motor 127 having a rotor mounted on a shaft and being encircled by the stator. Furthermore, the prior art treadmill 100 includes a shockload-smoothing flywheel 140 located external to the motor 127 and coupled to the shaft 130 of the motor 127. It would be beneficial to eliminate or combine the flywheel with the motor 127 to reduce the number of parts of the motor assembly 115.